#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>
int main ()
{
	char arr1[500] = {0};
	char arr2[128] = {0};
	int i = 0;
	int count = 0;
	int len = 0;
	gets(arr1);
	len = strlen(arr1);
	for(i=0;i<len;i++)
	{
	    arr2[(int)arr1[i]]++;
	}
	for(i=0;i<128;i++)
	{
	    if(arr2[i])
			count++;
	}
	printf("%d\n",count);
    return 0;
}





